Inverting logical expressions in JavaScript

Consider the following code:

javascriptif (num > 0 && num < 5) {
  console.log('+++');
} else {
  console.log('---');
}

Now our condition is following: num should be from 0 to 5. Let's invert this condition, that is, turn it into its opposite. The opposite condition is: num must be less than or equal to 0 OR greater than or equal to 5::

javascriptif (num <= 0 || num >= 5) {
  console.log('+++');
} else {
  console.log('---');
}

As you can see, in order to invert the condition, you have to think a little. It will be much easier to use the operator !, which is the logical NOT. Thanks to this operator, it is enough for us to put the sign ! before the initial condition, then it inverts itself:

javascriptif ( !(num > 0 && num < 5) ) {
  console.log('+++');
} else {
  console.log('---');
}

javascriptif (num1 >= 0 || num2 <= 10) {
  console.log('+++');
} else {
  console.log('---');
}